彭泽鲫两个雌核发育克隆的染色体组型分析

采用PHA和秋水仙素体内注射法直接制作肾细胞染色体标本,对彭泽鲫种群内两个不同雌核发育克隆的亲本进行染色体数目及组型分析。结果表明,彭泽鲫种群内的两个不同克隆存在染色体数目及组型差异,其中克隆H包含6条超数染色体在内的染色体众数是156,150条基本染色体的组型公式为：42M 36SM 39ST 33T,NF=228;克隆L包含12条超数染色体在内的染色体众数是162,150条基本染色体的组型公式为：36M 45SM 33ST 36T,NF=231。两个不同雌核发育克隆的发现及其染色体的差异说明彭泽鲫种群内同样存在着类似银鲫种群内的遗传多样性。     

Contributions to the cytotaxonomy of the Commelinaceae. Chromosome evolution in Tradescantia section Cymbispatha

The five species of Tradescantia section Cymbispatha studied, including one species T. poelliae D. R. Hunt, have chromosome numbers of In = 12, 14, 16, 22, 28, 30 and 36 and karyotypes of acrocentric, metacentric or telocentric chromosomes, or mixtures of both acrocentric and metacentric chromosomes. The numbers of major chromosome arms of these cytotypes give a nombre fondamentaP series of 14, 28, 42 and 56 which, in combination with meiotic analyses, indicates plants which, in genetical terms at least, are diploid, tetraploid, hexaploid and octoploid. This series has evolved from a 2 n = 14 acrocentric or telocentric karyotype by a combination of Robertsonian fusion and polyploidy. Pseudo-iso-chromosomes are sometimes formed in this evolutionary development and can persist as stable members of normal complements.     

Contributions to the cytotaxonomy of the Commelinaceae. Chromosome evolution in Tradescantia section Cymbispatha

The five species of Tradescantia section Cymbispatha studied, including one species T. poelliae D. R. Hunt, have chromosome numbers of In = 12, 14, 16, 22, 28, 30 and 36 and karyotypes of acrocentric, metacentric or telocentric chromosomes, or mixtures of both acrocentric and metacentric chromosomes. The numbers of major chromosome arms of these cytotypes give a nombre fondamentaP series of 14, 28, 42 and 56 which, in combination with meiotic analyses, indicates plants which, in genetical terms at least, are diploid, tetraploid, hexaploid and octoploid. This series has evolved from a 2 n = 14 acrocentric or telocentric karyotype by a combination of Robertsonian fusion and polyploidy. Pseudo-iso-chromosomes are sometimes formed in this evolutionary development and can persist as stable members of normal complements.     

Karyological differences of the Northern Dolly Varden Salvelinus malma malma and the white char Salvelinus albus from the Kamchatka River basin

The karyotypes of northern Dolly Varden and white char, sympathrically inhabiting the Kamchatka River basin, were studied. The karyotype of Dolly Varden was stable: 2n = 78 and NF = 98 + 2, while in white char, polymorphism and mosaicism for the chromosome number were revealed: 2n = 76-79, NF = 98 + 2. Using a routine chromosome staining technique, the karyotype of white char (2n = 78) was shown to be identical to that of Dolly Varden. In both karyotypes, similar sets of marker chromosomes were present: two pairs of submetacentric (SM), one pair of submeta-subtelocentric (SM-ST), one pair of large acrocentric (A), and one pair of large sub-telocentric (ST) chromosomes. However, the karyotypes of Dolly Varden and white char differed in the number and location of nucleolus organizer regions (NORs). In Dolly Varden, single NORs located in the telomeric regions of the marker SM-ST chromosomes were observed. In white char, NORs were multiple and located both in the telomeric regions of the marker SM-ST chromosomes and on the short and long arms of large ST chromosomes. The identical marker chromosomes indicate considerable phylogenetic relatedness between Dolly Varden and white char from the Kamchatka River basin. Variation in NORs provides evidence for the reproductive isolation of these chars and their species status.     

Cytogenetic Analysis and Chromosomal Characteristics of the Polymorphic 18S rDNA of Haliotis discus hannai from Fujian,China

We report on novel chromosomal characteristics of Haliotis discus hannai from a breeding population at Fujian, China. The karyotypes of H. discus hannai we obtained from an abalone farm include a common type 2n = 36 = 10M + 8SM (82%) and two rare types 2n = 36 = 11M + 7SM (14%) and 2n = 36 = 10M + 7SM + 1ST (4%). The results of silver staining showed that the NORs of H. discus hannai were usually located terminally on the long arms of chromosome pairs 14 and 17, NORs were also sometimes located terminally on the short arms of other chromosomes, either metacentric or submetacentric pairs. The number of Ag-nucleoli ranged from 2 to 8, and the mean number was 3.61 ± 0.93. Among the scored interphase cells, 41% had 3 detectable nucleoli and 37% had 4 nucleoli. The 18S rDNA FISH result is the first report of the location of 18S rDNA genes in H. discus hannai. The 18S rDNA locations were highly polymorphic in this species. Copies of the gene were observed in the terminal of long or/and short arms of submetacentric or/and metacentric chromosomes. Using FISH with probe for vertebrate-like telomeric sequences (CCCTAA)₃ displayed positive green FITC signals at telomere regions of all analyzed chromosome types. We found about 7% of chromosomes had breaks in prophase. A special form of nucleolus not previously described from H. discus hannai was observed in some interphase cells. It consists of many small silver-stained nucleoli gathered together to form a larger nucleolus and may correspond to prenucleolar bodies.     

黑线姬鼠华北亚种染色体研究

本文采用骨髓染色体制片法,对分布于山东的黑线姬鼠华北亚种的染色体组型,C-带、G-带和银染核型进行了分析研究。其核型为2n=48=38 T+8 M+XY。X为较小的端着丝粒染色体,Y为组型中最大的染色体。几乎每个常染色体的着丝粒区都具异染色质。性染色体的异染色质丰富。No.10和No.18染色体具NOR(?)。每条染色体都显示出较清晰的G-带。同时对黑线姬鼠精母细胞的减数分裂进行了观察,并将山东标本与欧洲标本的核型进行了比较,其性染色体有显著差异。     

Chromosomal evolution in the Brazilian lizards of genus Leposoma (Squamata, Gymnophthalmidae) from Amazon and Atlantic rain forests: banding patterns and FISH of telomeric sequences

An extensive karyotype differentiation was found among three species of gymnophthalmid lizard genus Leposoma which occur in the tropical forest areas of Brazil. We examined the chromosomes of the Amazonic species L. guianense (LOU) and L. oswaldoi (LOS) and the Atlantic forest species L. scincoides (LSC) after conventional and differential staining, and FISH of telomeric sequences. Both Amazonic species shared very similar 2n = 44 karyotypes, including 20 biarmed macrochromosomes and 24 microchromosomes (20 M + 24 m). However, the location of Ag-NORs and the amount of constitutive heterochromatin differed in these karyotypes. The Atlantic forest species L. scincoides has a very distinct karyotype with 52 acrocentric and subtelocentric chromosomes of decreasing size. Comparative R-banding analysis revealed complete homeology of the macrochromosomes of LGU and LOS and correspondence of banding patterns between LSC acrocentrics and subtelocentrics and some arms of biarmed LGU and LOS chromosomes. Pair 1 had similar banding patterns in the three species, implying the occurrence of a pericentric inversion. Interstitial telomeric bands (ITBs) detected by FISH at the pericentromeric region of some biarmed LGU and LOS chromosomes could be remnants of chromosomal rearrangements occurred during the differentiation of the karyotypes. Robertsonian rearrangements as well as pericentric inversions events probable were involved in the karyotype evolution of these Amazon and Atlantic forests species of Leposoma.     

Comparison of the Giemsa C-banded karyotypes of Hystrix coreana and H. patula (Poaceae, Triticeae)

The karyotypes of Hystrix coreana from eastern USSR and H. patula from USA were investigated by Giemsa C-banding. Both species are outbreeders and have 2n = 4x = 28. The karyotype of two plants of H. coreana has 10 metacentric, 6 submetacentric, 8 heterobrachial and 4 SAT chromosomes; two plants differed by having 12 metacentric, 4 submetacentric, 8 heterobrachial and 4 SAT-chromosomes, and 10 metacentric, 4 submetacentric, 9 heterobrachial and 5 SAT-chromosomes, respectively. The C-banding pattern had no or few inconspicuous intercalary bands, but conspicuous telomeric C-bands in one or both arms giving a high content of heterochromatin (16.3–18.2%). The chromosome complement of one plant of H. patula had 8 metacentric, 6 submetacentric, 8 heterobrachial and 6 SAT-chromosomes. The C-banding pattern had between 1 and 4 intercalary or centromeric bands and conspicuous telomeric bands on one or both arms giving a high content of constitutive heterochromatin (16.4%).     

Karyology and phylogeny of some Mesoamerican species of Zamia (Zamiaceae)

Chromosome numbers and karyotypes of four species of Zamia L. (Zamiaceae) are described. Plants of Z. manicata from Colombia are 2n = 18 with eight metacentric (M), four submetacentric (S), two acrocentric (A), and four telocentric (T) chromosomes. Plants of Z. ipetiensis from Panama are 2n = 23 with 3M + 4S + 2A + 14T. Plants of Z. cunaria from Panama have two different chromosome numbers, 2n = 23 with 3M + 4S + 2A + 14T and 2n = 24 with 2M + 4S + 2A + 16T. Plants of Z. acuminata from Costa Rica and Panama are 2n = 24 with 2M + 4S + 2A + 16T. On the basis of the occurrence of a one-to-two-ratio in the variation of M- and T-chromosome numbers in the karyotypes, centric fission or fusion are considered for their potential involvement in the chromosome variation of these plants. Data deriving from morphology and karyology, interpreted in a cladistic framework, suggest that centric fission rather than centric fusion is involved in the karyotype diversification of the four species and their closest Mesoamerican allies.     

云南三种角蟾的细胞遗传学研究

本文研究了云南三种角蟾的核型,C－带和Ag-NORs,结果显示宽头大角蟾,其2n=26(16M 8SM 2T),NF=50,5 8,No.10为T,次缢痕和Ag－NORs位于1p per,该区域同时还呈现C－带正染,其全部染色体的着丝点都有强弱不等的C－带染色;大花角蟾的核型2n=26(16M 8SM=2ST),NF＝50,5＋8,No.6为ST,次缢痕和Ag-NORs位于5q pes,全部着丝点均有C－带正染;凹顶角蟾5n=26(16M 4SM 6T),NF=46,6 7.No.11-13为T,次缢痕和Ag-NORs位于5q per,全部着丝点及周围均有浓C－带正染。三个种均未发现与性别相关的异形染色体,最后讨论了角蟾属核型演化的途径。     

Karyological Differences between Northern Dolly Varden Salvelinus malma malma and White Char Salvelinus albusfrom the Kamchatka River Basin

The karyotypes of northern Dolly Varden and white char, sympatrically inhabiting the Kamchatka River basin, were studied. The karyotype of Dolly Varden was stable: 2n= 78 andNF= 98 + 2, while in white char, polymorphism and mosaicism for the chromosome number were revealed: 2n= 76–79, NF= 98 + 2. Using a routine chromosome staining technique, the karyotype of white char (2n= 78) was shown to be identical to that of Dolly Varden. In both karyotypes, similar sets of marker chromosomes were present: two pairs of submetacentric (SM), one pair of submeta-subtelocentric (SM-ST), one pair of large acrocentric (A), and one pair of large subtelocentric (ST) chromosomes. However, the karyotypes of Dolly Varden and white char differed in the number and location of nucleolus organizer regions (NORs). In Dolly Varden, single NORs located in the telomeric regions of the marker SM-ST chromosomes were observed. In white char, NORs were multiple and located both in the telomeric regions of the marker SM-ST chromosomes and on the short and long arms of large ST chromosomes. The identical marker chromosomes indicate considerable phylogenetic relatedness between Dolly Varden and white char from the Kamchatka River basin. Variation in NORs provides evidence for the reproductive isolation of these chars and their species status.     

Chromosomes of three freshwater stingrays (Rajiformes Potamotrygonidae) from the Rio Negro basin, Amazon, Brazil

Potamotrygonidae is the representative family of South American freshwater elasmobranchs. It is a monophyletic group containing 20 species grouped into three genera. Three species belonging to two genera of this family were collected from the middle Negro River, Amazonas, Brazil, and studied cytogenetically: Paratrygon aiereba, Potamotrygon motoro and Potamotrygon orbignyi. Paratrygon aiereba presented 2n = 90 chromosomes and 4M+2SM+10ST+74A. Both species of Potamotrygon presented 2n = 66 chromosomes and differed in their chromosomal formulas: P. motoro had 18M+12SM+10ST+26A and P. orbignyi had 22M+10SM+8ST+26A. No sex heteromorphism was detected. The Fundamental Number (FN) was 106 for the three species. A system of multiple NORs was found in the three species, but with interspecific differences in terms of location and position of the active Ag-NORs sites. Paratrygon aiereba presented only four sites on the short arms of two chromosomal pairs, both in terminal regions. Potamotrygon motoro presented seven sites, on the long and short arms, all in terminal regions of non-homologous chromosomes; P. orbignyi presented eight sites on the long arms, all in terminal regions, of non-homologous chromosomes. The constitutive heterochromatin was in pericentromeric regions of all chromosomes, and no significant interspecific difference was found in relation to this marker.     

Karyotype structure, supernumerary chromosomes and heterochromatin distribution suggest a pathway of karyotype evolution in Dactylorhiza (Orchidaceae)

The relationships between Dactylorhiza romana and D. saccifera from southern Italy were analysed. These two species, both with 2 n = 2 x = 40 chromosomes and belonging to different sections of the genus, were distinguishable on the basis of karyotype structure and heterochromatin amounts and distribution. Their C-banded karyotypes differed considerably. D. saccifera showed most chromosomes with banded regions in the short arms, whereas in D. romana the bands were located mostly at telomeric regions of longer arms. Several individuals of D. romana had one or two very large heterochromatic supernumerary chromosomes. Based on evidence resulting from karyotype structure and heterochromatin distribution in the two species and on the genetic distances derived from the comparison of ITS sequences, it is suggested that D. romana represents a primitive form with respect to D. saccifera and is a possible intermediate step in the evolution of the genus Dactylorhiza from the 42-chromosome Orchis group. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 138 , 85–91.     

棕色田鼠的细胞遗传学研究

本次首次报告棕色田鼠（Microtus mandarinus)的核型,核型公式为2n=50=2(M,T) 2SM 44T XX(M,SM),XY(SM,ST),发现第一对常染色体及X性染色体存在多态现象,在所研究的15只雌性个体中有7只雌性个体的细胞只有1条X性染色体,性染色体组成为XO型,核型公式为2n=49=2(M,ST) 2SM 44T＋XO,。其中X性染色体不同于雄性中的X（SM）,为M类型,本文提出的综色田鼠3种核型与Brown等人（1964）提出的Microtus oregoni的3种核型（XO,YO,XY）有异,本文还阐述了染色体多态产生的机制和探讨了XO型个体发生的机理及其繁殖。     

中国五种锄足蟾科无尾两栖动物的细胞遗传学研究

本文对中国５种锄足蟾科无尾两栖动物的骨髓细胞有丝分裂中期作了细胞遗传学研究,内容包括核型、Ａｇ－ＮＯＲｓ和Ｃ－带。研究结果表明景东角蟾：２ｎ＝２６（２０Ｍ＋４ＳＭ＋２ＳＴ）,５＋８,ＳＣ和Ａｇ－ＮＯＲｓ位于６ｐ＾ｐｅｒ,同时呈Ｃ－带正染。Ｃ－带以着丝点区域正染为主;粗皮角蟾：２ｎ＝２６（２０Ｍ＋６ＳＭ）,５＋８,Ａｇ－ＮＯＲｓ在６ｑ＾ｉｎｔｅｒ,以着丝点Ｃ－带为主,但Ｎｏｓ．１２,１３有明显的端位     

Chromosomes and DNA of Mus: the karyotypes of M. fulvidiventris and M. dunni.

The chromosomes of the Asian mice, Mus fulvidiventris (booduga?), are typical of the Mus in general, viz., 40 telocentric chromosomes. The centromeric heterochromatin does not fluoresce brightly. The G band pattern of the euchromatin is the same as that of M. musculus. The diploid number of M. dunni is also 40, but each autosome possesses a short, heterochromatic second arm. The X chromosome is a long submetacentric, whose entire short arm and the terminal segment of the long arm are heterochromatic. The Y is a long telocentric and is heterochromatic. The G band pattern of the long arms of M. dunni involved only the addition of C bands. Mus dunni and M. booduga are sympatric in many localities in India, but they can be separated by karyological and subtle morphological differences.     

Variation of Giemsa C-band and fluorochrome banded karyotypes,and relationships inAllium subgen.Molium

The somatic karyotypes of 10 taxa belonging toAllium subgen.Molium (Liliaceae) from the Mediterranean area have been investigated using Giemsa C-band and fluorochrome (Hoechst, Quinacrine) banding techniques. A wide range of banding patterns has been revealed. InAllium moly (2n = 14),A. oreophilum (2n = 16) andA. paradoxum (2n = 16) C-banding is restricted to a region on each side of the nucleolar organisers and the satellites show reduced fluorescence with fluorochromes. The satellites are also C-banded and with reduced fluorescence inA. triquetrum (2n = 18), but two other chromosome pairs also have telomeric bands which are not distinguished by fluorochrome treatment. InA. erdelii (2n = 16) 4 pairs of metacentric chromosomes have telomeric C-bands while 2 pairs of telocentric chromosomes have centromeric C-banding. InA. subhirsutum (2n = 14),A. neapolitanum (2n = 28),A. trifoliatum subsp.hirsutum (2n = 14) andA. trifoliatum subsp.trifoliatum (2n = 21) chromosomes with long centromeres, consisting of a centromere and nucleolar organiser are positively C-banded on each side of the constriction. InA. subhirsutum banding is confined to the pair of chromosomes with this feature, whereas inA. neapolitanum one additional chromosome pair has telomeric bands and inA. trifoliatum there are varying numbers of chromosomes with centromeric and telomeric bands, depending on the subspecies.A. zebdanense (2n = 18) shows no C-bands. The banding patterns in this subgenus are compared with those recorded for otherAllium species and with the sectional divisions in the genus. Evidence from the banding patterns for allopolyploidy inA. trifoliatum subsp.trifoliatum andA. neapolitanum is discussed.     

Cytogenetic study on Microtus guentheri (Danford and Alston, 1880) (mammalia: rodentia) from Turkey: constitutive heterochromatin distribution and nucleolar organizer regions

Conventionally stained, C- and Ag-NOR banded karyotypes of Guenther's vole, Microtus guentheri were studied from Turkey. The species possesses a karyotype of 2n = 54, NFa = 52 and NF = 54 in specimens from Kahramanmara? and Gaziantep provinces, whereas NF = 56 in females and NF = 55 in males were found in individuals from Kirikkale and Nev?ehir provinces. The X chromosome was a large acrocentric (NF = 54) or submetacentric (NF = 55, 56) while the Y chromosome was a small telocentric in all specimens examined. Blocks of constitutive heterochromatin were located in the pericentromeric areas of autosomes including the X chromosome. Nucleolar organizer regions (NORs) were located at the telomeric regions of the short arms of five acrocentric pairs and centromeric regions of two telocentric pairs in the Nev?ehir and Kirikkale specimens.     

Variation in karyotype in Hemerocallis.

Fifty two taxa have been studied, out of which forty five, including the species; H. citrina, H. dumortierii, H. multiflora, H. forrestii and H. thunbergil are diploid with 22 chromosomes in the somatic complement. H. fulva var. Europa, H. fulva var. cypriana, H. kwanso "Flore Pleno" and H. disticha "Flore Pleno" are triploid with thirty three chromosomes in the somatic complement. One cultivar "Mrs. David Hall" is tetraploid with forty four chromosomes. Besides this two aneuploid clones "Garden Lady" and cv. "29" with 2n=23 and 2n=29 chromosomes respectively were also encountered. Essentially four basic karyotypes are recognizable; A(IV + 8L + 1J + 1I), B(IV + 7L + 2J + 1I), C(9L+ 1J + 1I) and d(8L + 2J + 1I), where V stands for median, L for submedian, J for subterminal and I for terminal centromere. Thirty two taxa could be relegated to these four types and 17 can be resolved as combinations of these four types. These fall under AB, AC, AD or BC, BD and CD classes. The number of nucleolar chromosomes does not show any correlation with the grade of ploidy, whereas 2, 3 or telocentric chromosomes were consistantly found in diploid, triploid and tetraploid taxa respectively. The possible origin of telocentric chromosomes and aneuploid taxa has been discussed.     

Constitutive heterochromatin DNA polymorphisms in diploid Medicago sativa ssp. falcata.

A Giemsa C-banding technique was used to study the amount and location of constitutive heterochromatin in diploid (2n = 2x = 16) Medicago sativa ssp. falcata (L.) Arcangeli. Most accessions had the standard C-banding pattern with centromeric bands on all the chromosomes and a prominent heterochromatic band at the nucleolar organizer regions (NOR) of the satellited (SAT) chromosomes. However, we observed in various accessions that constitutive heterochromatic C-bands can exist at the telomeric ends of all the chromosomes. Interstitial bands occurred on the short arms of all chromosomes except for chromosome 3 and on the long arms of chromosomes 1, 2, 3, and 6, only. Rearranged chromosomes such as isochromosomes have been observed for the short arms of chromosomes 2 and 6. This is the first report on the existence of C-banding polymorphisms and the detection of putative isochromsomes in the chromosomes of diploid ssp. falcata which could have contributed to the variation observed in cultivated alfalfa.